Polymer bromination process in solution

ABSTRACT

An improved process is provided for the bromination of isoolefin-conjugated diolefin polymers by brominating said polymer in solution in selected halogen-containing hydrocarbons as solvent. There is also provided an improved product of said process wherein the brominated polymer contains not less than 80 percent of the bound bromine atoms in a form suitable to participate in the vulcanization of the polymer and wherein not less than 70 percent of the bound conjugated diolefin units are similarly so brominated.

FIELD OF THE INVENTION

[0001] This invention relates to an improved process for the brominationof isoolefin polymers and to the product produced by such an improvedprocess.

BACKGROUND OF THE INVENTION

[0002] Isoolefin polymers have been known for many years and arecommercially available as polymers of an isoolefin and a conjugateddiolefin, especially of isobutylene and isoprene. While such polymershave a wide range of desired properties they are not readilycovulcanizable with highly unsaturated polymers, such as polymerscontaining high proportions of one or more conjugated diolefin. In orderto overcome such a problem, isoolefin-conjugated diolefin polymers, andespecially isobutylene-isoprene polymers which are also known as butylpolymers, have been halogenated. The halogenation, especiallychlorination or bromination, is achieved by treating the butyl polymerin solution in an inert organic solvent with controlled quantities ofchlorine or bromine. The resulting halogenated butyl polymer has theinherent satisfactory properties of the butyl polymers while also beingcovulcanizable with the highly unsaturated polymers.

[0003] The halogenation process is well known to be rather inefficient.One reason for the inefficiency is that for every atom of chlorine orbromine that is incorporated into the polymer a molecule of hydrogenchloride or hydrogen bromide is formed. Another reason is that some ofthe hydrogen chloride or hydrogen bromide may add to the polymer forminga chemically undesirable group. A further reason is that the actualefficiency of utilization of the chlorine or bromine is quite low,generally being of the order of about 25 to about 40 percent by weight.

DESCRIPTION OF THE PRIOR ART

[0004] The preparation of butyl polymers is well known wherein a mixtureof an isoolefin, preferably isobutylene, and a conjugated diolefin,preferably isoprene, in an inert diluent, preferably methyl chloride, isreacted at a temperature of from about −80° C. to about −120° C. in thepresence of a Friedel-Crafts catalyst, preferably aluminum chloride. Thebutyl polymer so produced contains about 95 to about 99.5 mole percentof isobutylene and from about 0.5 to about 5 mole percent of isoprene.Such a polymer is dissolved in an organic solvent and reacted, at about10° C. to about 60° C., with, preferably, chlorine or bromine forsufficient time to yield a polymer containing not more than 1 atom ofcombined chlorine per double bond in the polymer or not more than 3, andpreferably not more than 1, atoms of combined bromine per double bond inthe polymer—see for example U.S. Pat. Nos. 2,944,578 and 3,011,996. U.S.Pat. No. 3,018,275 describes a process for the halogenation of butylpolymers wherein an oxidizing agent, including a material selected fromhydrogen peroxide, sodium peroxide, sodium chlorate or bromate andsodium hypochlorite, is present during the halogenation process toincrease the utilization of the halogenating agent in the process.

SUMMARY OF THE INVENTION

[0005] It is an objective of this invention to provide an improvedprocess for the bromination of isobutylene polymers by increasing theutilization of the bromine in the process.

[0006] It is another objective of this invention to provide an improvedbrominated butyl polymer by use of the improved process.

[0007] Accordingly, one aspect of the invention provides an improvedprocess for the bromination of a C₄-C₆ isoolefin-C₄-C₆ conjugateddiolefin polymer which comprises preparing a solution of said polymer ina solvent, adding to said solution bromine and reacting said brominewith said polymer at a temperature of from about 10° C. to about 60° C.and separating the brominated isoolefin-conjugated diolefin polymer, theamount of bromine being from about 0.3 to about 1.0 moles per mole ofconjugated diolefin in said polymer, the improvement being that saidsolvent comprises an inert halogen-containing hydrocarbon, saidhalogen-containing hydrocarbon comprising a halogenated C₂ to C₆paraffinic hydrocarbon or a halogenated aromatic hydrocarbon.

[0008] In one aspect, the present invention provides an improved processfor the bromination of a C₄-C₆ isoolefin-C₄-C₆ conjugated diolefinpolymer which comprises preparing a solution of said polymer in asolvent, adding to said solution bromine and reacting said bromine withsaid polymer at a temperature of from about 10° to about 60° C. andseparating the brominated isoolefin-conjugated diolefin polymer, theamount of bromine being from about 0.3 to about 1.0 moles per mole ofconjugated diolefin in said polymer, the improvement being that saidsolvent comprises an inert halogen-containing hydrocarbon selected fromthe group consisting of ethyl bromide, propyl chloride, n-butyl chlorideand monochlorobenzene.

[0009] In another aspect, the solvent further contains up to 20 volumepercent of water.

[0010] One aspect of the invention provides for the process wherein thesolvent further contains up to 20 volume percent of an aqueous solutionof an oxidizing agent. The oxidizing agent is soluble in water and issuitable to oxidize the hydrogen bromide to bromine in the processsubstantially without oxidizing the polymeric chain. In a particularaspect, the oxidizing agent is an oxygen containing oxidizing agentselected from the group comprising sodium hypochlorite, hydrogenperoxide, sodium peroxide, sodium chlorate, bromate, or other suitableoxidizing agents.

[0011] In yet another aspect, the solvent further contains up to 20volume percent of an aqueous solution of sodium hypochlorite, the amountof sodium hypochlorite being equivalent to not more than about 200percent of the moles of bromine added.

[0012] In a further aspect, this invention provides an improvedbrominated isoolefin-conjugated diolefin polymer produced by theaforesaid process wherein the brominated polymer contains from about 1to about 4 weight percent of bromine based on the brominated polymer andnot less than about 80 percent of the bound bromine atoms are present ina form suitable to participate in the vulcanization of said polymer andnot less than about 70 percent of the 1,4-isoprene units in the originalisoolefin-conjugated diolefin polymer are converted in the brominatedpolymer into a form suitable to participate in the vulcanization of saidpolymer.

DETAILED DESCRIPTION OF THE INVENTION

[0013] Isoolefin-conjugated diolefin polymers are well known in the artas also is the process for the manufacture of such polymers. Isoolefinsare selected from the C₄ to C₆ isoolefins with isobutylene being thepreferred isoolefin. Conjugated diolefins are selected from the C₄ to C₆conjugated diolefins with isoprene being the preferred conjugateddiolefin. Such polymers comprise from about 95 to about 99.5 molepercent of the isoolefin, preferably from about 97 to about 99.5 molepercent of isobutylene, and from about 0.5 to about 5 mole percent ofconjugated diolefin, preferably from about 0.5 to about 3 mole percentof isoprene. The polymer is prepared by the cationic polymerization ofthe isoolefin and conjugated diolefin, in an inert diluent which ispreferably methyl chloride or ethyl chloride, at a temperature of fromabout −80° C. to about −120° C. in the presence of a Friedel-Craftscatalyst which is preferably aluminum chloride.

[0014] For the prior art bromination process, the polymer is dissolvedin an inert hydrocarbon solvent such as pentane, hexane and heptane andthe solution is fed to a halogenation reactor. The halogenation reactoris typically a vessel equipped with inlet and outlet lines and anagitator. Bromine is also fed to the halogenation reactor at acontrolled rate in relation to the amount of polymer and the double bondcontent of the polymer. The material from the reactor is treated with anaqueous alkaline solution, such as sodium hydroxide, to neutralize thehydrogen bromide formed in the halogenation reaction and to react withresidual bromine and then contacted with hot water and steam to removethe solvent and produce a slurry of brominated polymer in water which isthen handled in a conventional manner to yield the essentially drybrominated polymer. Stabilizers for the brominated polymer may be addedduring the recovery process.

[0015] Such prior art processes exhibit poor utilization of the brominein the halogenation process, due to the formation of one molecule ofhydrogen bromide for each atom of bromine incorporated into the polymer,due to the addition of a small amount of the hydrogen bromide into thepolymer and due to the need to use more bromine than is actuallyincorporated into the polymer.

[0016] We have now discovered that the halogenation process can besignificantly improved by the use as the solvent for the polymer asolvent which comprises an inert halogen-containing hydrocarbon, morespecifically a halogenated C₂ to C₆ paraffinic hydrocarbon or ahalogenated aromatic hydrocarbon. Preferably, the inerthalogen-containing hydrocarbon is selected from the group consisting ofethyl bromide, propyl chloride, n-butyl chloride and monochlorobenzene.The solvent may also contain up to about 20, preferably from about 3 toabout 15, volume percent, based on the total solvent, of water. Further,the solvent may also contain up to about 20, preferably from about 3 toabout 15, volume percent of an aqueous solution of an oxidizing agentsuch as an oxygen containing oxidizing agent selected from the groupcomprising sodium hypochlorite, hydrogen peroxide, sodium peroxide,sodium chlorate or bromate. The oxidizing agent is soluble in water andis suitable to oxidize the hydrogen bromide to bromine in the processsubstantially without oxidizing the polymeric chain. Weak oxidizingagents at low concentration, such as sodium hypochlorite, are preferredin order to prevent or minimize oxidation of the polymer. Preferably,the oxidizing agent will comprise an aqueous solution of sodiumhypochlorite, the amount of sodium hypochlorite being equivalent to notmore than about 200, preferably from about 100 to about 140, percent ofthe moles of bromine added to the process.

[0017] Using such a solvent for the polymer leads to an increase in theamount of bromine which is incorporated into the polymer to formchemical structures that participate in the vulcanization of saidpolymer. We have found that for a fixed reaction time in the process ofthe present invention in excess of about 85 mole percent of the brominesupplied to the process is incorporated into the polymer to formchemical structures that participate in the vulcanization of thepolymer. In contrast, in the prior art only about 60 to 70 mole percentof the bromine is so incorporated. When the solvent includes water, theimprovement in the utilization of bromine is believed to be due to thehydrogen bromide formed in the reaction being preferably soluble in thewater and thus not so readily available to form hydrogen bromideaddition structures. When the solvent includes aqueous sodiumhypochlorite, the improvement in the utilization of bromine to form thedesired chemical structures may be as high as about 190 mole percent ofthe bromine supplied to the process—this is believed to be due to thehydrogen bromide formed in the reaction being oxidized by the sodiumhypochlorite to form bromine which may then further react with thepolymer.

[0018] Without intending to limit the scope of the invention, thebromine utilization improvement is believed to be achieved by theincrease of the dielectric constant of the reaction medium via the useof select halogen-containing hydrocarbons as solvent for theisoolefin-conjugated diolefin polymers instead of an inert hydrocarbonsolvent. It is believed that the dielectric constant of thehalogen-containing hydrocarbon could be used as a guide for theselection of proper reaction medium for the process of this invention.Table A lists the dielectric constant of some halogen-containinghydrocarbons and hexane. It is apparent from Table A that not all thehalogen-containing hydrocarbons will be suitable for the process of thisinvention. For example, the dielectric constant of carbon tetrachlorideis just slightly higher than that of hexane, therefore only marginalimprovement can be expected. In contrast use of solvents with highdielectric constant, such as monochlorobenzene, n-butyl chloride, ethylbromide, should lead to exceptional results. To achieve desired results,the dielectric constant will be greater than that of carbontetrachloride.

[0019] In some of the halogenated solvents listed in Table A, solubilityof the polymer may be limited. In such cases addition of some paraffinichydrocarbon is recommended to aid dissolution of the polymer. TABLE ADielectric Constant of Some Solvents Halogenated solvent Dielectricconstant @ 45° C. Hexane 1.85 Carbon tetrachloride 2.19 Chloroform 4.38Bromobenzene 5.11 Chlorobenzene 5.30 n-Butyl chloride 6.42 Bromoethane8.16 Methylene chloride 8.23 Methyl chloride 8.64 Dichloroethane 9.17

[0020] Such a discovery means that the amount of bromine supplied to theprocess may be reduced, that the amount of excess bromine leaving thehalogenation reactor with the brominated polymer may be reduced which inturn reduces the quantity of aqueous alkaline solution required to reactwith it, that the amount of bromine chemically bound in the polymer maybe more effectively used in the subsequent vulcanization process andthat the unsaturation level in the polymer (that is the amount of boundconjugated diolefin) may be reduced because with the more completeutilization of the bromine more of the unsaturated double bonds in thepolymer are effectively brominated than in the prior art processes.

[0021] The desired chemical structures in the brominated polymer includethe exo allylic bromide structure, the endo allylic bromide structureand the re-arranged exo allylic bromide structure. In all of these casesthe bromine atom is present attached to a carbon atom which is in anallylic configuration with a carbon-carbon double bond (i.e. C═C—CBr)wherein exo and endo have the conventional meanings. In these cases, thebromine atom is chemically very active and participates in thesubsequent vulcanization process. The quantities of these variouschemical structures may be readily determined by 500 MHz HNMR with highlevels of accuracy. The exo allylic bromide structure is the predominantone and usually forms about 75 to about 85 percent of the desiredchemical structures. The total primary structure thus refers to thetotal of the exo allylic bromide, the endo allylic bromide and there-arranged exo allylic bromide and the product of the present processcontains not less than about 80 percent of the bound bromine atoms inthese configurations which are the form to actively participate in thesubsequent vulcanization process. The process of the present inventionleads to a high conversion of the bound 1,4-isoprene units into theprimary structure. The present process leads to such conversions of notless than 70 and up to about 90 or more percent into the primarystructure whereas the prior art processes lead to such conversions ofonly about 50 to about 60 percent. The total primary structure as apercentage of the bound 1,4-isoprene units clearly shows the aboveeffect.

[0022] The halogenation process may be operated at a temperature of fromabout 10° C. to about 60° C., preferably from about 20° C. to about 50°C. and the reaction time may be from about 1 to about 10 minutes,preferably from about 1 to about 5 minutes. The pressure in thehalogenation reactor may be from about 0.8 to about 10 bar.

[0023] The brominated polymer recovered from the halogenation processtypically has a molecular weight, expressed as the Mooney viscosity (ML1+8 at 125° C.), of from about 25 to about 55. Brominated polymer suchas bromobutyl polymer contains from about 0.5 to about 3, mostpreferably from about 1 to about 2, mole percent of isoprene and fromabout 97 to about 99.5, most preferably from about 98 to about 99, molepercent of isobutylene based on the hydrocarbon content of the polymer,and from about 1 to about 4, preferably from about 1.5 to about 3,weight percent of bromine based on the bromobutyl polymer. Further, theproduct of the present process contains not less than about 80 percentof the bound halogen atoms in a form suitable to participate in thevulcanization of the polymer. In the product of the prior art, a smallamount of the bound halogen is present in the polymer as a result of theaddition of a hydrogen bromide molecule across a carbon-carbon doublebond thereby forming a saturated group in which the bromine atom isessentially inert in the vulcanization process. In the product of thepresent process, the amount of bound bromine present in the polymer as aresult of the addition of a hydrogen bromide molecule across acarbon-carbon double bond is reduced from that of the prior art.Analysis of the polymer by 500 MHz HNMR was the method used to determinethe structural composition of the brominated polymers. Inisobutylene-isoprene polymers, the isoprene bound in the1,4-configuration in the HNMR spectrum exhibits a resonance at about 5.1ppm. In the brominated isobutylene-isoprene polymers, the HNMR spectrumexhibits resonances at about 5.4, 5.05 and 4.35 ppm which correspond tothe exo allylic bromide structure, at about 5.6 ppm which correspond tothe endo allylic bromide structure, at about 4.08 and 4.10 ppm whichcorrespond to the re-arranged exo allylic bromide structure. Thehydrobrominated structure is calculated from the mass balance. Also inthe product of the present process, the proportion of the carbon-carbondouble bonds that have been reacted with a bromine atom (to form anunsaturated bromine containing group which is active in thevulcanization process) is much higher than is the case for the productof the prior art processes. Hence the product of the present processcontains a higher proportion of the bound bromine atoms in a formsuitable to participate in the vulcanization process.

[0024] The brominated polymer is used to make vulcanizates. Thevulcanization of polymers is well known. Carbon black is well known inthe art for the reinforcement of vulcanizates and is added to thepolymer during the compounding process. Hydrocarbon extender oils arealso well known materials used in the compounding process. Generally thecarbon black will be selected from the furnace and channel carbon blacksand may be used in amounts of from about 20 to about 90 parts by weightper 100 parts by weight of polymer. Hydrocarbon extender oils may beselected from the paraffinic, naphthenic and aromatic oils, preferablyfrom the paraffinic and naphthenic oils, and may be used in amounts fromabout 5 to about 40 parts by weight per 100 parts by weight of polymer.The vulcanization systems for use with the present product are thosealready known in the art for use with bromobutyl polymers and generallywill include a metal oxide, at least one sulphur based accelerator and,optionally, elemental sulphur. A suitable metal oxide is zinc oxide usedin an amount of from about 1 to about 7 parts by weight per 100 parts byweight of polymer. Suitable sulphur based accelerators may be selectedfrom the thiuram sulphides, the thiocarbamates, the thiazyl compoundsand the benzothiazyl compounds. The amounts of such accelerators may befrom about 0.3 to about 3 parts by weight per 100 parts by weight ofpolymer. Elemental sulphur may be present in an amount up to about 2parts by weight per 100 parts by weight of polymer. Various stabilizers,antioxidants, tackifiers, etc. may also be added during the compoundingprocess. The compounding itself will be by conventional methods using arubber mill or an internal mixer, controlling the temperature to keep itbelow about 80° C., in one or two stages, generally with the cure activecomponents being added last. The so-formed compounds are then shaped andvulcanized by heating for from about 5 to about 60 minutes attemperatures of from about 150° C. to about 200° C.

EXAMPLE Example 1

[0025] To a 0.5 L glass reactor, equipped with a stirrer and two reagentaddition ports, was added a solution of 20 g of butyl polymer (anisobutylene-isoprene polymer containing 1.77 mole percent of isoprene)in 270 mL of solvent. The solvent used is shown in Table I. The polymersolution, with the agitator in operation, was heated to 45° C. followingwhich 18 mL of water or an aqueous sodium hypochlorite solution wasadded and dispersed thoroughly throughout the solution. The reactionmixture was protected from light to avoid light induced bromination ofthe polymer or the solvent. Through one of the reagent addition portswas added 0.18 mL of bromine and agitation of the mixture was continued.After a reaction time of two minutes, the reaction was stopped by theaddition, through the second reagent addition port, of 20 mL of a 6%solution of sodium hydroxide. Stabilizers for the polymer were added,the solution was washed with distilled water until neutral and thebrominated polymer was recovered by removing the bulk of the solvent ina rotary evaporator followed by final drying in a vacuum oven.

[0026] Analysis of the polymers by 500 MHz HNMR gave the results shownin Table I. Experiment #1 was a control because hexane was used as thesolvent. The improvements in the nature of the product are clearly seenin the results.

Example 2

[0027] Using the procedures described in Example 1, further solventswere evaluated as shown in Table II, the Experiments #6 and 7 beingcontrols. TABLE I Expt. # 1 2 3 4 5 Solvent - hexane (mL) 270 — — — — -ethyl bromide (mL) — 270 270 — — - n-butyl chloride (mL) — — — 270 270 -H₂O (mL) 18 18 — 18 — - NaOCl/H₂O (mL) — — 18 — 18 Product CompositionExo structure (mole %) 0.53 0.88 1.32 0.74 1.29 Total primary structure(mole %) 0.61 0.94 1.46 0.79 1.37 Unreacted isoprene (mole %) 1.05 0.660.2 0.91 0.29

[0028] TABLE II Expt. # 6 7 8 9 Solvent - Carbon tetrachloride (mL) 270270 — — - monochlorobenzene (mL) — — 270 270 - H₂O (mL) — 18 — 18-NaOCl/H₂O (mL) — 18 — 18 Product Composition Exo structure (mole %)0.69 1.00 0.89 1.4 Total primary structure (mole %) 0.78 1.22 0.96 1.53Unreacted isoprene (mole %) 0.87 0.45 0.66 0.15 Hydrobrominatedstructure (mole %) 0.12 0.1 0.15 0.09 Bromine utilization (mole %) 80.2125.8 98.6 158.6 Total primary structure as % of total bromine present %86.6 91.9 86.5 94.7 Total primary structure as % of bound 1,4-isopreneof 44.1 68.9 54.2 86.4 original polymer %

Definitions

[0029] The term Inert in relation to halogenated solvents means solventsthat are inert with respect to reaction with bromine under theconditions of bromination.

[0030] It is of course, understood that the above examples are submittedmerely to illustrate the invention and there is no intention to limitthe invention to them. Resort may be had to various modifications andvariations of the present invention without departing from the spirit ofthe discovery or the scope of the appended claims.

[0031] The embodiments of the invention in which an exclusive propertyor privilege is claimed are defined as follows:

What is claimed is:
 1. An improved process for the bromination of aC₄-C₆ isoolefin-C₄-C₆ conjugated diolefin polymer which comprisespreparing a solution of said polymer in a solvent, adding to saidsolution bromine and reacting said bromine with said polymer at atemperature of from about 10° C. to about 60° C. and separating thebrominated isoolefin-conjugated diolefin polymer, the amount of brominebeing from about 0.3 to about 1.0 moles per mole of conjugated diolefinin said polymer, the improvement being that said solvent comprises aninert halogen-containing hydrocarbon, said halogen-containinghydrocarbon comprising a halogenated C₂ to C₆ paraffinic hydrocarbon ora halogenated aromatic hydrocarbon.
 2. An improved process for thebromination of a C₄-C₆ isoolefin-C₄-C₆ conjugated diolefin polymer whichcomprises preparing a solution of said polymer in a solvent, adding tosaid solution bromine and reacting said bromine with said polymer at atemperature of from about 10° C. to about 60° C. and separating thebrominated isoolefin-conjugated diolefin polymer, the amount of brominebeing from about 0.3 to about 1.0 moles per mole of conjugated diolefinin said polymer, the improvement being that said solvent comprises aninert halogen-containing hydrocarbon selected from the group consistingof ethyl bromide, propyl chloride, n-butyl chloride andmonochlorobenzene.
 3. The process of claim 1 wherein said solventfurther contains up to 20 volume percent of water.
 4. The process ofclaim 2 wherein said solvent further contains up to 20 volume percent ofwater.
 5. The process of claim 1 wherein the solvent further contains upto 20 volume percent of an aqueous solution of an oxidizing agent thatis soluble in water and suitable to oxidize the hydrogen bromide tobromine in the process substantially without oxidizing the polymericchain.
 6. The process of claim 2 wherein the solvent further contains upto 20 volume percent of an aqueous solution of an oxidizing agent thatis soluble in water and suitable to oxidize the hydrogen bromide tobromine in the process substantially without oxidizing the polymericchain.
 7. The process of claim 1 wherein the solvent further contains upto 20 volume percent of an oxygen containing oxidizing agent selectedfrom the group comprising sodium hypochlorite, hydrogen peroxide, sodiumperoxide, sodium chlorate or bromate.
 8. The process of claim 2 whereinthe solvent further contains up to 20 volume percent of an oxygencontaining oxidizing agent selected from the group comprising sodiumhypochlorite, hydrogen peroxide, sodium peroxide, sodium chlorate orbromate.
 9. The process of claim 1 wherein said solvent further containsup to 20 volume percent of an aqueous solution of sodium hypochlorite,the amount of sodium hypochlorite being equivalent to not more thanabout 200 percent of the moles of bromine added.
 10. The process ofclaim 2 wherein said solvent further contains up to 20 volume percent ofan aqueous solution of sodium hypochlorite, the amount of sodiumhypochlorite being equivalent to not more than about 200 percent of themoles of bromine added.
 11. The process of claim 3 wherein said solventfurther contains up to 20 volume percent of an aqueous solution ofsodium hypochlorite, the amount of sodium hypochlorite being equivalentto not more than about 200 percent of the moles of bromine added. 12.The process of claim 4 wherein said solvent further contains up to 20volume percent of an aqueous solution of sodium hypochlorite, the amountof sodium hypochlorite being equivalent to not more than about 200percent of the moles of bromine added.
 13. The process of claim 2wherein the isoolefin-conjugated diolefin polymer is anisobutylene-isoprene polymer comprising from about 97 to about 99.5 molepercent of isobutylene and from about 0.5 to about 3 mole percent ofisoprene.
 14. The process of claim 2 wherein the isoolefin-conjugateddiolefin polymer is an isobutylene-isoprene polymer comprising fromabout 97 to about 99.5 mole percent of isobutylene and from about 0.5 toabout 3 mole percent of isoprene, the solvent is selected from the groupconsisting of ethyl bromide and n-butyl chloride, the reaction is at atemperature of from about 20° to about 50° C. and the reaction time isfrom about 1 to about 5 minutes.
 15. The process of claim 3 wherein theisoolefin-conjugated diolefin polymer is an isobutylene-isoprene polymercomprising from about 97 to about 99.5 mole percent of isobutylene andfrom about 0.5 to about 3 mole percent of isoprene, the solvent is ahalogen-containing hydrocarbon selected from the group consisting ofethyl bromide and n-butyl chloride and water forming from about 3 toabout 15 volume percent of the solvent, the reaction is at a temperaturefrom about 20° to about 50° C. and the reaction time is from about 1 toabout 5 minutes.
 16. The process of claim 4 wherein theisoolefin-conjugated diolefin polymer is an isobutylene-isoprene polymercomprising from about 97 to about 99.5 mole percent of isobutylene andfrom about 0.5 to about 3 mole percent of isoprene, the solvent is ahalogen-containing hydrocarbon selected from the group consisting ofethyl bromide and n-butyl chloride and an aqueous solution of sodiumhypochlorite forming from about 3 to about 15 volume percent of thesolvent, the reaction temperature is from about 20° to about 50° C. andthe reaction time is from about 1 to about 5 minutes.
 17. The process ofclaim 5 wherein the isoolefin-conjugated diolefin polymer is anisobutylene-isoprene polymer comprising from about 97 to about 99.5 molepercent of isobutylene and from about 0.5 to about 3 mole percent ofisoprene, the solvent is a halogen-containing hydrocarbon selected fromthe group consisting of ethyl bromide and n-butyl chloride and anaqueous solution of sodium hypochlorite forming from about 3 to about 15volume percent of the solvent, the reaction temperature is from about20° to about 50° C. and the reaction time is from about 1 to about 5minutes.
 18. The product of the process of claim 14 wherein thebrominated isobutylene-isoprene polymer contains from about 1 to about 4weight percent of bromine based on the brominated polymer and not lessthan about 80 percent of the bound bromine atoms are present in a formsuitable to participate in the vulcanization of said polymer and notless than about 70 percent of the 1,4-isoprene units in the originalisobutylene-isoprene polymer are converted in the brominated polymerinto a form suitable to participate in the vulcanization of saidpolymer.
 19. The product of the process of claim 15 wherein thebrominated isobutylene-isoprene polymer contains from about 1 to about 4weight percent of bromine based on the brominated polymer and not lessthan about 80 percent of the bound bromine atoms are present in a formsuitable to participate in the vulcanization of said polymer and notless than about 70 percent of the 1,4-isoprene units in the originalisobutylene-isoprene polymer are converted in the brominated polymerinto a form suitable to participate in the vulcanization of saidpolymer.
 20. The product of the process of claim 16 wherein thebrominated isobutylene-isoprene polymer contains from about 1 to about 4weight percent of bromine based on the brominated polymer and not lessthan about 80 percent of the bound bromine atoms are present in a formsuitable to participate in the vulcanization of said polymer and notless than about 70 percent of the 1,4-isoprene units in the originalisobutylene-isoprene polymer are converted in the brominated polymerinto a form suitable to participate in the vulcanization of saidpolymer.
 21. The product of the process of claim 1 .